Wound dressings comprising a backing layer and a layer of hydrocolloid adhesive are well known, such dressings may be known as hydrocolloid dressings. Whereas these dressings are excellent for application to blisters or slowly exuding wounds, they may be difficult to attach to fast exuding wounds, such as a bleeding wound or skin abrasion. Hydrocolloid adhesive is capable of absorbing large amounts of moisture, but not instantaneously as their initial absorption is low.
Typically, the hydrocolloid dressings have a continuous surface against the skin or wound which does not absorb liquid instantaneously. This leads to the issue of small drops of fluid being squeezed across the surface of the dressing during application of the dressing to the wound and this fluid may be squeezed all the way to the edge of the dressing leading to poor adhesion and premature detachment. There have been different attempts to solve problems with initial absorption:
One approach is to optimize the adhesive to a faster initial absorption, e.g. by increasing the amount of hydrocolloid. However, the increase in hydrocolloid may lead to a decrease in adhesive tack and thereby a shorter wear time for the wound dressing. Thus, the increase in absorption rate required to deal with the fluid production rate is not compatible with a well adhering hydrocolloid dressing.
Another way is to provide the wound dressing with an absorbent center zone, such as a pad of an absorbent material, such as a gauze or foam or cellulosic material. This will add an extra step in the production and the resulting product may be more visible and less flexible. Furthermore, adding an absorbent pad fundamentally changes the nature of the hydrocolloid dressing as the benefits of having the hydrocolloid adhesive over the wound bed will not be present anymore.
An object of the present invention is to provide an absorbent dressing capable of providing an increased initial release of a pharmaceutically active agent directly to e.g. a blister or open wound. It is an additional object of the present invention to provide such an absorbent dressing that can handle exudates from wounds and e.g. rupturing blisters while providing said initial release directly thereto.